Chrysosplenium ramosissimum Y.I.Kim & Y.D.Kim, 2018

Kim, Yong-In, Cho, Seong-Hyun, Lee, Jung-Hoon, Kang, Dae-Hyun, Jin Hee Park, & Kim, Young-Dong, 2018, Chrysosplenium ramosissimum Y. I. Kim & Y. D. Kim (Saxifragaceae), a new species from Korea, PhytoKeys 111, pp. 1-10 : 3-6

Chrysosplenium ramosissimum Y.I.Kim & Y.D.Kim sp. nov. Figs 1 , 2 , 3A1, A2 , 4A 가지털괭이눈 (Ga-ji-teol-gwaeng-i-nun)

Diagnosis.

Chrysosplenium ramosissimum is most similar to the sympatric species C. valdepilosum , but the former is readily distinguishable by the presence of yellowish-green (vs. bright yellow) bracteal leaves during flowering, highly branched and elongated sterile branches after fruiting (Fig. 4 ), shiny silvery dots on sterile branch leaves and larger tubercles on the seed coat (Fig. 3 ).

Type.

SOUTH KOREA. Gangwon-do: along a stream near a hiking trail to Guksa Seonghwangsa (temple), Mt. Seonjaryeong, Hoenggye-ri, Daegwallyeong-myeon, Pyeongchang-gun, 37°41'25.80"N, 128°45'27.22"E, elev. 872 m, 24 Apr. 2015, KYI-2015001 (holotype HHU; isotypes HHU, KB).

Perennial herbs.

Small, tender, hermaphroditic. Roots fibrous. Flowering stem erect, 2-6 cm long, pilose, light green or reddish to purple, with 2-5 sterile branches arising from base; sterile branches creeping after fruiting, elongated over 30 cm, 2 or more times branched at axils, densely pilose. Leaves opposite, basal and cauline, simple, estipulate, petiolate. Basal leaves 1 or 2 pairs, withered before flowering. Leaves on flowering stem, 1 pair, attached at 1/2 or below of the stem; petioles 1-5 mm, pilose; blade 2-5 × 2-8 mm, flabelliform, apex subtruncate to rounded, base attenuate, margins obscurely undulate to crenate or distinctly obtusely dentate (3-6 teeth), translucent white or brown ciliate, both surfaces glabrous. Leaves on sterile branches with long internode (to 8 cm at fruiting); petioles 2-12 mm, pilose; blade to 2 × 2.5 cm, suborbicular or widely ovate (upper ones), flabellate (lower ones), apex rounded, base cuneate, margins crenate with 5-10 flat obscure teeth on each side, translucent white or brown ciliate, upper surface glabrous, densely silvery dotted, pale green, lower surface pilose on veins, greenish-grey. Inflorescence 4- to 9-flowered cyme, surrounded by leaf-like bracts; pedicels ca. 1 mm, sparsely pilose. Bracteal leaves yellowish-green during flowering, turning to light green or green after fruiting; petioles 1-3 mm, pilose; blades 2-6 × 2-10 mm, obdeltoid, upper surface glabrous, densely silvery dotted, lower surface glabrous, greenish-grey, margins obscurely undulate to crenate or distinctly obtusely dentate, 2-5 teeth, translucent white or brown ciliate, obtuse to subtruncate at apex, base narrowly cuneate to cuneate. Flowers tetramerous; sepals 4, free, petaloid, 1 pair overlapping the other in bud, erect, yellow, widely ovate to widely subelliptic, ca. 2.5-3 × ca. 2 mm, glabrous, 3-veined, persistent, apex obtuse to truncate, slightly recurved; petals absent; stamens 8, in 2 section, ca. 1.3 mm, shorter than sepal; filaments filiform, 0.8-0.9 mm long; anthers yellow, 2-locular, 0.45-0.5 mm long, longitudinally dehiscent; pistil 2-carpellate, semi-inferior, ovary 1-locular, ovules at 2 parietal placentae, styles 2, free, ca. 1 mm long, stigma round, disc absent. Fruit capsule, pale green, glabrous, ca. 5.5 mm long, 2-lobed (horn shaped), lobes dehiscent along adaxial suture, slightly unequal; seeds numerous, dark brown, ellipsoid, with a carina on one side, thick-walled, 0.8-1.0 × 0.65-0.75 mm, with hemispheroidal tubercles, tubercles ca. 15 μm in diameter, seed surface covered with minute deciduous papillae.

Distribution.

Chrysosplenium ramosissimum is only known to exist on Mt. Seonjaryeong in Gangwon-do, Korea, at an elevation of 630-910 m. To date, only one population of approximately 2,000 individuals has been discovered, near a small creek. In the absence of additional data, we presently score it as Data Deficient (DD), according to the IUCN Red List criteria ( IUCN 2001).

Ecology.

Chrysosplenium ramosissimum occurs in deciduous forests of mountain valleys, where it grows in humid and semi-shaded areas near small creeks along with Quercus mongolica Fisch. ex Ledeb., Fraxinus rhynchophylla Hance and Acer buergerianum Miq. The flowering period of this species is late March to early May and the fruiting period is late May to early July.

Etymology.

The specific epithet of the new species refers to the highly branched sterile branches after fruiting.

Additional specimens examined (paratype).

SOUTH KOREA. Gangwon-do: Mt. Seonjaryeong, Hoenggye-ri, Daegwallyeong-myeon, Pyeongchang-gun, 37°41'25.80"N 128°45'27.22"E, elev. 872 m, 24 Apr. 2015, KYI-2015002 (HHU), KYI-2015003 (HHU), KYI-2015004 (HHU), KYI-2015005 (HHU), KYI-2015006 (HHU); 37°41'33.65"N 128°45'25.26"E, elev. 872 m, 16 Apr. 2016, KYI-2016001 (HHU), KYI-2016002 (HHU), KYI-2016003 (HHU), KYI-2016004 (HHU), KYI-2016005 (HHU), KYI- 2016006 (HHU).

Key to taxa of Chrysosplenium section Pilosa modified from Hara (1957)

Figures

Figure 1. Chrysosplenium ramosissimum Y. I. Kim & Y. D. Kim. A Flowering individual B fruiting individual C sterile branch habit after fruiting D inflorescence and bracteal leaves E-F flower G stamen at various stages H flower longitudinal section I infructescence and bracteal leaves J capsule with persistent sepals K capsule, sepals removed L capsule, longitudinal section M capsule, before dehiscence (top view) N capsule, after dehiscence (top view) O node of sterile branch, enlarged P seed, side view (left), top view (right) Q seed coat, enlarged.

Figure 2. Chrysosplenium ramosissimum Y. I. Kim & Y. D. Kim. A Inflorescence with bracteal leaves B sterile branches and basal leaves during flowering with withered basal leaves C sterile branch leaves with shiny silvery spots during flowering D sterile branch after fruiting E plant habit during flowering.

Figure 3. Upper surface of sterile branch leaves of Chrysosplenium ramosissimum (A 1) and C. valdepilosum (B 1). Scanning electron micrograph of seeds of C. ramosissimum (A 2) and C. valdepilosum (B 2).

Figure 4. Sterile branch outline of Chrysosplenium ramosissimum (A) and C. valdepilosum (B) after fruiting.